Enzyme Research Reveals Folic Acid Prevents Heart Disease, Birth D

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Enzyme Research Reveals How Folic Acid Prevents Heart Disease,

Birth Defects

by Alison Davis

 

 

Scientists have known for decades that folic acid, one of the B

vitamins, can protect against certain birth defects--such as spina

bifida--that develop in the first few weeks after conception. For this

reason, the Food and Drug Administration (FDA) recommends that every

woman of child-bearing age supplement her diet with 400 extra

micrograms of this vitamin. Folic acid supplements may also decrease

the incidence of heart attacks and strokes in both men and women. More

recent findings have suggested the way in which folic acid does its

molecular good deeds, by lowering levels of a potentially harmful

compound called homocysteine, a risk factor for heart attacks and

strokes.

Drs. Rowena Matthews and Martha Ludwig, both of the University of

Michigan, have succeeded in showing that folic acid performs this task

by speeding up the conversion of homocysteine to an amino acid, called

methionine, that the body needs to fuel myriad chemical reactions.

Folic acid saves the day, the researchers show, by improving the fit

between an enzyme and a helper molecule called a cofactor. The enzyme

in this case is methylenetetrahydrofolate reductase (MTHFR), and the

cofactor, a molecule called FAD, is also vitamin-derived (from vitamin

B2) and is essential for converting homocysteine to methionine. The two

scientists, who for years have been studying how the MTHFR enzyme

works, determined that folic acid performs its protective role in the

body by locking FAD onto MTHFR.

Besides bolstering the FDA guidelines on the importance of dietary

folic acid for pregnant women, the new results provide solid evidence

for the molecule's important and more general role in reducing

homocysteine levels that are dangerously high in a variety of unhealthy

states, such as heart disease. The work also points to possible

therapies for these diseases, by upping folic acid intake in the diet,

either through foods rich in the vitamin or vitamin pills.

REFERENCE

Guenther BD, Sheppard CA, Tran P, Rozen R, Matthews RG, Ludwig ML.

The structure and properties of methylenetetrahydrofolate reductase

from Escherichia coli suggest how folate ameliorates human

hyperhomocysteinemia. Nature Structural Biology 1999;6:359-65.

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who can comment on this work.